Touch sensor with integrated signal bus extensions

ABSTRACT

A touch sensor may be formed from a flexible substrate such as a sheet of polymer. The flexible substrate may have a main rectangular portion and a protruding portion. Capacitive touch sensor electrodes may be formed on the upper and lower surfaces of the flexible substrate. Signal lines may be coupled to the touch sensor electrodes. The ends of the signal lines may extend onto the protruding portion. Signal lines may be formed on upper and lower surfaces of the flexible substrate. The signal lines may be coupled to circuitry on a printed circuit using a connector that receives the end of the protruding portion. Ground structures on the protruding portion may be configured to overlap the signal lines or may be laterally interposed between upper surface signal lines and lower surface signal lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/363,648, filed Feb. 1, 2012 (U.S. PatentApplication Publication No. 2013/0194759), the contents of which areincorporated by reference herein in their entirety for all purposes.

BACKGROUND

This relates generally to sensors, and more particularly, to touchsensors for electronic devices.

Electronic devices such as portable computers and cellular telephonesare often provided with displays. Touch sensitive displays are oftenused to provide users with the ability to interact with a displaythrough touch-based commands. Touch sensitive displays can beimplemented using capacitive touch sensor. Capacitive touch sensors mayalso be used in forming computer track pads and other input devices.

A capacitive touch sensor may include an array of touch sensorelectrodes. In configurations such as those in which the touch sensor isbeing used as part of a display, the touch sensor electrodes may beformed from pads of transparent conductive material such as indium tinoxide. When a user brings a finger or other external object into thevicinity of the touch sensor electrodes, touch sensor circuitry candetect changes in capacitance on the touch sensor electrodes. Thesedetected capacitance changes can be processed to generate touch eventdata for controlling an electronic device.

To satisfy consumer demand for small form factor devices, capacitivetouch sensor arrays are sometimes formed on thin flexible substratessuch as sheets of polyimide. A flexible printed circuit signal busformed from a separate strip of polyimide can be attached to the edge oftouch sensor substrate to route signals from the touch sensor to a logicboard within a device.

The signal lines in the flexible printed circuit bus may be attached tothe capacitive touch sensor substrate using anisotropic conductive film.Care must be taken not to impose excessive stress on anisotropicconductive film bonds between the flexible printed circuit bus and thetouch sensor substrate, because excessive stress may lead to reliabilityissues. This type of restriction on the amount of acceptable stress forthe anisotropic conductive film bonds may impose undesired constraintson use of the flexible printed circuit bus when installing a touchsensor in an electronic device. For example, the acceptable bend radiusfor the flexible printed circuit bus may be limited. There may also beadditional cost and complexity associated with attaching the flexibleprinted circuit bus to the touch sensor.

It would therefore be desirable to be able to provide improved touchsensors for electronic devices.

SUMMARY

An electronic device may have a display mounted in a housing. A touchsensor may be mounted over the display or may be mounted in otherportions of the device.

The touch sensor may be formed from a flexible substrate such as a sheetof polymer. The flexible substrate may have a main rectangular portionand a protruding portion that protrudes from one or more edges of themain rectangular portion.

Capacitive touch sensor electrodes and associated signal lines may beformed on the upper and lower surfaces of the flexible substrate. Thesignal lines may be coupled to the touch sensor electrodes. The signallines may extend onto the protruding portion of the flexible substrate.The signal lines on the protruding portion of the flexible substrate maybe coupled to circuitry on a printed circuit using one or moreconnectors.

Ground structures on the protruding portion may be configured to overlapthe signal lines or may be laterally interposed between upper surfacesignal lines and lower surface signal lines.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of an illustrative electronicdevice having a touch sensor in accordance with an embodiment of thepresent invention.

FIG. 2 is a top view of an illustrative touch sensor having integralflexible printed circuit bus structures in accordance with an embodimentof the present invention.

FIG. 3 is a top view of an illustrative touch sensor having integralflexible printed circuit bus structures on protruding tail portions thatare attached to each other using adhesive in accordance with anembodiment of the present invention.

FIG. 4 is a cross-sectional side view of a flexible printed circuit busstructure having signal traces on an upper surface and a groundstructure on an opposing lower surface in accordance with an embodimentof the present invention.

FIG. 5 is a cross-sectional side view of a flexible printed circuit busstructure having signal traces on a lower surface and a ground structureon an opposing upper surface in accordance with an embodiment of thepresent invention.

FIG. 6 is a cross-sectional side view of a flexible printed circuit busstructure formed by attaching bus structures of the type shown in FIG. 4to bus structures of the type shown in FIG. 5 using adhesive inaccordance with an embodiment of the present invention.

FIG. 7 is a top view of a touch sensor with an integral flexible printedcircuit bus structure having regions with traces on an upper surface,regions with traces on a lower surface, and regions with traces on boththe upper and lower surfaces in accordance with an embodiment of thepresent invention.

FIG. 8 is a cross-sectional side view of an illustrative configurationthat may be used for the regions of the flexible printed circuit busstructure of FIG. 7 that include traces on both upper and lower surfacesin accordance with an embodiment of the present invention.

FIG. 9 is a cross-sectional side view of another illustrativeconfiguration that may be used for the regions of the flexible printedcircuit bus structure of FIG. 7 that include traces on both upper andlower surfaces in accordance with an embodiment of the presentinvention.

FIG. 10 is a cross-sectional side view of an illustrative touch sensorwith an integral flexible printed circuit tail section having traces onits lower surface that is attached to a printed circuit using aconnector in accordance with an embodiment of the present invention.

FIG. 11 is a cross-sectional side view of an illustrative touch sensorwith an integral flexible printed circuit tail section having traces onits upper surface that is attached to a printed circuit using aconnector in accordance with an embodiment of the present invention.

FIG. 12 is a cross-sectional side view of an illustrative touch sensorwith an integral flexible printed circuit tail having traces on itsupper and lower surfaces that may be attached to a printed circuit usinga connector in accordance with an embodiment of the present invention.

FIG. 13 is a top view of a portion of a touch sensor with an integralflexible printed circuit bus structure showing illustrative bend axislocations along which the flexible printed circuit bus structure may bebent in accordance with an embodiment of the present invention.

FIG. 14 is a top view of an illustrative touch sensor showing howintegral flexible printed circuit bus structures may protrude outwardsalong one or more sides of a main rectangular portion of the touchsensor and may reduce signal path in accordance with an embodiment ofthe present invention.

FIG. 15 is a top view of an illustrative touch sensor showing howintegral flexible printed circuit bus structures may protrude outwardsalong two different edges of a rectangular touch sensor substrate inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Electronic devices such as electronic device 10 of FIG. 1 may beprovided with one or more touch sensors such as touch sensor 12.

As shown in FIG. 1, device 10 may have a housing such as housing 14.Housing 14 may be formed from metal, glass, ceramic, plastic,fiber-based composites, other materials, or combinations of thesematerials.

A display such as display 20 may be mounted in housing 14. Display 20may be a liquid crystal display, an organic light-emitting diodedisplay, a plasma display, an electrowetting display, an electrophoreticdisplay, or a display formed using other display technologies. Display20 may be formed from one or more rigid substrate layers (e.g., one ormore glass substrate layers) and/or one or more flexible substratelayers (e.g., one or more polymer layers).

Display cover layer 16 may cover display 20. Display cover layer 16 maybe formed from glass, plastic, or other transparent material. Touchsensor 12 may be mounted between display 20 and display cover layer 16using a layer of adhesive such as adhesive 18. If desired, touch sensor12 may be mounted in housing 12 of device 10 using other arrangements.For example, touch sensor 12 may be attached to the upper surface ofdisplay structures 20 or may be incorporated into the layers of materialthat make up display structures 20. Touch sensors such as touch sensor12 may also be incorporated into non-display components such as trackpads or other input devices.

The touch sensor elements that form touch sensor 12 may be based on anysuitable touch sensor technology such as acoustic touch technology,force-sensor-based touch technology, resistive touch technology, orcapacitive touch technology (as examples). In capacitive touch sensors,capacitive electrodes may be formed from a conductive material. Forexample, for use in display applications in which the touch sensorelectrodes are transparent to allow a user to view an underlyingdisplay, the touch sensor electrodes may be formed from a transparentconductive material such as indium tin oxide. Configurations in whichtouch sensor 12 is a capacitive touch sensor and in which touch sensorelectrodes for touch sensor 12 are formed from transparent conductivematerials are sometimes described herein as an example. Other types ofarrangements may be used for touch sensor 12 if desired (e.g.,arrangements with non-capacitive sensors, arrangements with capacitiveelectrodes formed from materials other than indium tin oxide, etc.).

The capacitive electrodes of touch sensor 12 may be formed on asubstrate such as a transparent substrate. For example, the touch sensorelectrodes may be formed on a rectangular clear flexible plasticsubstrate such as a sheet of polyimide or other polymer. As shown inFIG. 1, the substrate for touch sensor 12 may have an integral portionsuch as portion 26 that protrudes outward from the edges of the mainportion of the touch sensor substrate. Portion 26 may be a flexible tailportion or other extending portion of touch sensor 12 that includes asignal bus for routing signals between display 12 and control circuitrysuch as control circuitry on printed circuit board 22.

One or more electronic components such as components 24 may be mountedin housing 14 of device 10. Components 24 may include integratedcircuits, discrete components such as capacitors, resistors, andinductors, switches, speakers, microphones, connectors, and otherelectrical components. Components 24 may be mounted on one or moreprinted circuit boards such as printed circuit 22. Printed circuit 22may be, for example, a rigid printed circuit board such as a boardformed from fiberglass-filled epoxy (e.g., FR4) or may be a flexibleprinted circuit (“flex circuit”) formed from a flexible sheet ofpolyimide or other flexible polymer. Components 24 may include surfacemount technology (SMT) parts and other components that are mounted onprinted circuit 22 using solder (as an example). The circuits that aremounted on printed circuit 22 may include, for example, one or moreintegrated circuits for controlling the operation of touch sensor 12. Asan example, components 24 may include a touch sensor integrated circuitthat converts raw capacitance data from touch sensor electrodes on touchsensor 12 into touch event data for processing by applications andoperating system functions running on device 10.

Protruding flexible tail portion 26 of the touch sensor substrate mayinclude conductive lines (e.g., metal traces) that form a signal bus.The signal bus may be used to conveying signals between touch sensorelectrodes that are located on the main portion of touch sensor 12 thatis located under cover layer 16 and components 24 on printed circuit 22.As shown in FIG. 1, end 28 of flexible tail portion 26 of touch sensor12 may be connected to printed circuit 22 using one or more connectorssuch as connector 74. If desired, other attachment mechanisms may beused for connecting signal lines in portion 26 of touch sensor 12 toprinted circuit 22 (e.g., conductive bonds formed from solder,conductive bonds formed from anisotropic conductive film, etc.). The useof connectors such as connector 74 to connect portions such as portion26 of touch sensor 12 to circuitry on printed circuit 22 is merelyillustrative.

Tail portion 26 of touch sensor 12 may be formed from one or moreextending (protruding) portions of the substrate used to form touchsensor 12. An illustrative configuration is shown in FIG. 2. As shown inthe example of FIG. 2, touch sensor 12 may have a substrate such assubstrate 32. Substrate 32 may have a main portion such as main portion33 with a rectangular outline or other suitable shape. Protrudingportion 26 may be formed from integral extending portions of substrate32 that extend outwards from one or more of the edges of main portion33.

Capacitive electrodes such as electrodes 34 and 38 may be formed onsubstrate 32. Electrodes 34 and 38 may have any suitable shapes (e.g.,squares, diamonds, elongated rectangles, etc.). In the illustrativeconfiguration of FIG. 2, electrodes 34 and 38 have the shape ofelongated rectangles (i.e., strips). Electrodes 34 extend horizontallyto form rows. Electrodes 38 extend vertically to form columns. Bymonitoring capacitance changes associated with the horizontal andvertical electrodes, touch sensor 12 may be used to ascertain thelocation of an external object such as finger 36 during a touch event(i.e., when a user of device 10 brings finger 36 in contact with coverglass 16 or otherwise brings finger 36 into close proximity to sensor12).

Conductive lines such as conductive lines 40 may each be coupled to arespective one of electrodes 34 and may be routed from main portion 33(e.g., a rectangular planar portion) of substrate 32 to protrudingportion 26. Conductive lines 42 may each be coupled to a respective oneof electrodes 38 and may likewise be routed from main portion 33 toprotruding portion 26. In protruding portion 26, signal lines such aslines 40 and 42 may run parallel to each other and may form signal buses(i.e., protruding portion 26 may form an integral flexible printedcircuit bus for touch sensor 12).

Conductive electrodes 38 and 34 may, if desired, be formed on the sameside of substrate 32. In this type of arrangement, an interveningdielectric coating layer may be used to prevent electrodes 38 and 34from being shorted to each other. In the illustrative configuration ofFIG. 2, electrodes 34 and 38 are formed on opposing surfaces ofsubstrate 32. In particular, electrodes 34 and associated signal routinglines 40 have been formed on the upper surface of substrate 32, whereaselectrodes 38 and associated signal routing lines 42 have been formed onthe lower surface of substrate 32.

Conductive lines 40 and 42 may be formed from conductive material suchas metal (e.g., copper), transparent conductive material such as indiumtin oxide, or other conductive substances. For example, conductive lines40 and 42 may be copper lines, indium tin oxide lines, or lines thatinclude a lower layer of indium tin oxide and an upper layer of copper(as examples).

Main portion 33 of substrate 32 may have a rectangular shape, a shapewith curved edges, a shape with straight edges, a shape with curved andstraight edges, or other suitable shapes. When mounted to a planarsupport structure such as planar cover glass 16 or planar displaystructures 20, main portion 33 may be maintained in a planar state. Ifdesired, main portion 33 may be mounted to a curved surface (e.g., acurved cover glass, etc.).

Protruding structure 26 may extend from one or more edges of mainportion 33. For example, protruding structure 26 may have three separatetab-shaped (e.g., rectangular) extending portions that each extend fromthe lower edge of main portion 33, as shown in FIG. 2. In this type ofarrangement, portion 26 may have one or more sections (labeled “T” inFIG. 2) that are used to support lines 40 (i.e., signal lines on the topof substrate 32), and one or more sections (labeled “B” in FIG. 2) thatare used to support lines 42 (i.e., signal lines on the lower surface ofsubstrate 32). Lines 40 extend from the upper surface of substrate 32 tothe upper surface of sections T. Within sections T of extended portion26, lines 40 generally run parallel to each other and form a signal bus.Lines 42 extend from the lower surface of substrate 32 to the lowersurface of section B of extended portion 26, where lines 42 form asignal bus.

In the example of FIG. 2, there is one “B” section and two “T” sections.This type of arrangement may help minimize the need for the linesassociated with upper electrodes 34 (i.e., lines 40) from crossing thelines associated with lower electrodes 38 (i.e., lines 42). Minimizingcrossing of the upper and lower signal lines in touch sensor 12 mayimprove touch sensor signal quality by reducing spurious signals due tounwanted coupling between the upper and lower lines. There may, ingeneral, be any suitable number of “T” and “B” sections in extendingportion 26. These sections of portion 26 may extend laterally from thelower edge of main portion 33, from one or more side edges of mainportion 33, and/or from the top edge of portion 33.

As shown in FIG. 3, sections T and B may be configured to overlap. Thistype of structure may be formed by laminating multiple polymer sheetstogether (as an example). With a configuration of the type shown in FIG.3, sections T and B do not overlap in regions 56. In regions 58, portion26T of sections T overlaps portion 26B of section B.

A cross-sectional side view of section T of extending portion 26 ofsubstrate 32 of FIG. 2 taken along line 50 and viewed in direction 44 isshown in FIG. 4. As shown in FIG. 4, section T of extending portion 26may include signal lines 40 that run along the upper surface ofsubstrate 32 and an overlapping ground structure such as ground 60 thatruns under the signal lines along the lower surface of substrate 32.Ground 60 may be formed from metal (e.g., copper), transparent conductor(e.g., indium tin oxide), a layered structure having a lower layer ofindium tin oxide and an upper layer of copper or other metal, or othersuitable conductive materials.

A cross-sectional side view of section B of extending portion 26 ofsubstrate 32 of FIG. 2 taken along line 46 and viewed in direction 48 isshown in FIG. 5. As shown in FIG. 5, section B of extending portion 26may include signal lines 42 that run along the lower surface ofsubstrate 32 and an overlapping ground structure such as ground 62 thatruns on top of the signal lines along the upper surface of substrate 32.Ground 62 may be formed from metal (e.g., copper), transparent conductor(e.g., indium tin oxide), a layered structure having a lower layer ofindium tin oxide and an upper layer of copper or other metal, or othersuitable conductive materials.

FIG. 6 is a cross-sectional side view of region 58 of extending portion26 of touch sensor substrate 32 showing how upper section T may beattached to lower section B using adhesive such as adhesive 64.

As shown in the top view of touch sensor 12 in FIG. 7, extending portion26 may, if desired, include sections T and B that merge into a section“T/B” that includes signal lines on both upper and lower surfaces ofsubstrate 32. Sections T and B may extend from different portions of thelower edge of main portion 33 of substrate 32 and may be separated byoptional openings such as openings 66 in substrate 32. In sections T,lines 40 may run in parallel on the upper surface of substrate 32whereas ground 60 may cover some or all of the lower surface ofsubstrate 32. In section B, lines 42 may run in parallel on the lowersurface of substrate 32 whereas ground 62 may cover some or all of theupper surface of substrate 32. In section T/B of extended portion 26 ofsubstrate 32, lines 42 may be run in parallel along the upper surface ofsubstrate 32 and lines 42 may run along the lower surface of substrate32. To avoid signal interference, it may be desirable to laterallyoffset lines 40 and 42 so that they do not overlap each other.

FIG. 8 is a cross-sectional side view of an illustrative section T/B ofextended portion 26 of touch sensor substrate 32 of FIG. 7 taken alongline 68 and viewed in direction 70. As shown in the illustrativeconfiguration of FIG. 8, lines 40 and lines 42 may be formed onprotruding portion 26 of common substrate 32. Lines 40 may run parallelto each other along the upper surface of substrate 32. Lines 42 may runparallel to each other along the lower surface of substrate 32. Tominimize signal interference, lines 40 and lines 42 may be formed indifferent areas, so that lines 40 and lines 42 are laterally offset fromeach other and do not overlap. As shown in FIG. 8, for example, lines 40may be formed on the right-hand side of section T/B and lines 42 may beformed on the left-hand side of section T/B.

Grounding structures may be provided on substrate 32 such as groundstructures 62 and 60. In the illustrative configuration of FIG. 8,ground structures 62 are formed on the upper surface of substrate 32 andoverlap lines 42, whereas ground structures 60 are formed on the lowersurface of substrate 32 and overlap lines 40. In the illustrativeconfiguration of FIG. 9, ground structures 62 on the upper surface ofsubstrate 32 are laterally interposed between lines 40 and 42, but donot overlap lines 42. Similarly, ground structures 60 on the lowersurface of substrate 32 of FIG. 9 are laterally interposed between lines42 and 40, but do not overlap lines 40. If desired, other configurationsmay be used (e.g., with ground structures 62 that partly overlap lines42 and/or ground structures 60 that partly overlap lines 40, etc.).

The signal lines on extending portion 26 may be coupled to circuitry ona printed circuit such as printed circuit 22 of FIG. 1. Signal lineconnections between extended portion 26 of substrate 32 and circuitry indevice 10 such as circuitry on printed circuit 22 may be formed usingsolder, anisotropic conductive film, connectors, other connectiontechniques, or combinations of these arrangements.

As shown in FIG. 10, for example, section B of extended portion 26 maybe inserted into a connector such as connector 70 on printed circuit 22.Printed circuit 22 may include conductive paths (e.g., metal traces)such as path 72. Paths such as paths 72 may be coupled to electricalcomponents such as component 24 (e.g., using solder). Extended portion26 may include section B. Section B may be bent so that portion 26 maybe received in connector 74. Signal lines 42 may be formed on the lowersurface of substrate 32 in section B.

Connector 74 may have a connector housing such as connector housing 76.Metal structures such as metal spring structure 78 may be formed inhousing 76 and may be used in interconnecting lines 42 to paths 72. Asshown in FIG. 10, metal structure 78 may have a spring portion such asspring portion 80 that contacts a respective one of lines 42. Portion 82of metal structure 78 may be connected to path 72 using solder 84 (as anexample). Ground structures on extending portion 26 (not shown in FIG.10) may be coupled to paths on printed circuit 22 using a separate metalstructure. FIG. 11 shows how section T of extended portion may becoupled to printed circuit 22 using a connector such as connector 74.When section T of substrate 32 is inserted in connector 74, signal linessuch as signal line 40 of FIG. 11 may be coupled to path 72 via metalstructure 78 and solder 84. Ground structures on extending portion 26(not shown in FIG. 11) may be coupled to printed circuit 22 using aseparate metal structure.

If desired, connector 74 may include multiple metal structures such asmetal structures 78A and 78B of FIG. 12. With this type ofconfiguration, connector 74 may be used to form both upper and lowersignal lines connections for a portion of extending portion 26 (e.g.,section T/B such as sections T/B of FIGS. 8 and 9). As shown in FIG. 12,signal lines such as single line 40 may be coupled to paths 72 onprinted circuit 22 using metal structures such as structure 78B andsignal lines such as signal line 42 may be coupled to paths 72 onprinted circuit 22 using metal structures such as structure 78A. Groundstructures on extending portion 26 (not shown in FIG. 12) may likewisebe coupled printed circuit 22 using metal structures in connector 74.

One or more sections of extended portion 26 of touch sensor substrate 32may be connected to printed circuit 22 using connectors such asconnector 74 of FIG. 10, connector 74 of FIG. 11, and/or connector 74 ofFIG. 12 (e.g., one or more “B” sections, one or more “T” sections and/orone or more “T/B” sections).

FIG. 13 is a top view of an illustrative portion of substrate 32 oftouch sensor 12 showing illustrative locations for a bend axis alongwhich substrate 32 may be bent when installed within housing 14. Asshown in FIG. 13, substrate 32 may be bent along a bend axis such asbend axis 90 or a bend axis such as bend axis 88 to allow protrudingportion 26 to be bent (see, e.g., FIGS. 1, 10, 11, and 12). If desired,substrate 32 may be bent along a bend axis such as bend axis 86 thatintersects substrate 32 in main portion 33 (i.e., main portion 33 ofsubstrate 32 may be bent in addition to or instead of bending protrudingportion 26 of substrate 32). Configurations for touch sensor 12 in whichsubstrate 32 is not bent may also be used.

Protruding portion 26 of substrate 32 may be formed along any suitableedge of main portion 33 of substrate 32. In the example of FIG. 14,protruding portion 26 has two sections (“T”) formed as protrudingextensions of the left and right edges of main portion 33 of substrate32 on which parallel upper signal lines 40 are used to form signalbuses. Protruding portion 26 also has two sections (“B”) formed asprotruding extensions of upper and lower edges of main portion 33 ofsubstrate 32 on which parallel lower signal lines 42 are used to formsignal buses.

By arranging sections of protruding portion 26 on each of the edges ofsubstrate 32 as shown in FIG. 14, the length of signal lines such assignal lines 40 and 42 that are used in conveying signals between thecapacitive touch sensor electrodes and protruding portion 26 can beminimized. Because the length of signal lines 40 and 42 can be reduced,less area is consumed by signal lines. As a result, the width W aroundthe periphery of main portion 33 that is consumed by signal traces canbe minimized and the inactive portion of touch sensor 12 can beminimized.

In the example of FIG. 14, protruding portion 26 protrudes from each ofthe four edges of rectangular main portion 33 of substrate 32. FIG. 15is a top view of touch sensor 12 in an illustrative configuration inwhich protruding portion 26 extends from two of the four edges of mainportion 33. Configurations in which different numbers of sectionsprotrude from main portion 33 may be used (e.g., configurations withmore than one section protruding from each side of main portion 33,configurations with extending sections on all four edge, on three edges,on two edges, or on one edge of portion 33, etc.).

The foregoing is merely illustrative of the principles of this inventionand various modifications can be made by those skilled in the artwithout departing from the scope and spirit of the invention.

1. A touch sensor panel, comprising: a flexible substrate including amain portion having a main width and a plurality of capacitive touchsensor electrodes coupled to a plurality of signal lines disposedthereon; and one or more extending portions extending from a common edgeof the main portion, each of the extending portions having an extendingportion width narrower than the main width; wherein the one or moreextending portions include first and second sections, each of the firstand second sections having one or more of the plurality of signal linesformed on only one side of the extending portion and not on the otherside of the extending portion.
 2. The touch sensor panel of claim 1,wherein the flexible substrate comprises a flexible sheet of polymer,and wherein the main portion comprises a rectangular main portion havingfour edges, one of the four edges being the common edge.
 3. The touchsensor panel of claim 1, wherein some of the plurality of capacitivetouch sensor electrodes are formed on a first surface of the flexiblesubstrate, and wherein some of the plurality of capacitive touch sensorelectrodes are formed on a second surface of the flexible substrate. 4.The touch sensor panel of claim 3, wherein the first section includes afirst ground structure on the second surface that at least partiallyoverlaps at least one of the plurality of signal lines on the firstsurface, and wherein the second section includes a second groundstructure on the first surface that at least partially overlaps at leastone of the plurality of signal lines on the second surface.
 5. The touchsensor panel of claim 3, wherein the plurality of capacitive touchsensor electrodes comprise indium tin oxide and wherein the plurality ofsignal lines comprise a conductive material selected from the groupconsisting of metal and indium tin oxide.
 6. The touch sensor panel ofclaim 3, wherein the one or more extending portions further includes athird section that includes one or more of the plurality of signal lineson the first surface and a ground structure on the second surface thatoverlaps at least some of the plurality of signal lines on the firstsurface.
 7. An electronic device, comprising: a housing; a displaymounted in the housing; and a touch sensor panel that at least partiallyoverlaps the display, wherein the touch sensor panel includes a flexiblesubstrate having a main portion including a common edge with a mainwidth and a plurality of separated extending portions extending from thecommon edge and having one or more extending portion widths less thanthe main width, and a plurality of signal lines formed on opposing firstand second surfaces of the main portion and the plurality of separatedextending portions; wherein a first extending portion of the pluralityof separated extending portions includes one or more of the plurality ofsignal lines formed only on the first surface and not on the secondsurface, and wherein a second extending portion of the plurality ofseparated extending portions includes one or more of the plurality ofsignal lines formed only on the second surface and not on the firstsurface.
 8. The electronic device of claim 7, wherein at least one ofthe separated extending portions is bent.
 9. The electronic device ofclaim 7, wherein the touch sensor panel comprises a plurality ofcapacitive touch sensor electrodes on the flexible substrate and whereinthe plurality of signal lines are coupled to the plurality of capacitivetouch sensor electrodes.
 10. The electronic device of claim 7, whereinthe touch sensor panel further comprises a ground structure on thesecond surface that at least partially overlaps the one or more signallines on the first surface.
 11. The electronic device of claim 7,wherein the one or more of the plurality of signal lines formed only onthe first surface are laterally offset from the one or more of theplurality of signal lines formed only on the second surface, and whereinthe touch sensor panel further comprises: first ground structures on thesecond surface of the first extending portion that at least partiallyoverlap the one or more of the plurality of signal lines formed only onthe first surface; and second ground structures on the first surface ofthe second extending portion that at least partially overlap the one ormore of the plurality of signal lines formed only on the second surface.12. The electronic device of claim 7, wherein the first and secondextending portions overlap each other in an overlapping region andwherein the touch sensor panel further comprises: first groundstructures on the second surface of the first extending portion in theoverlapping region, wherein the first ground structures are laterallyinterposed between the one or more of the plurality of signal lines;second ground structures on the first surface of the second extendingportion in the overlapping region, wherein the second ground structuresare laterally interposed between the one or more of the plurality ofsignal lines.
 13. The electronic device of claim 9, further comprising:a printed circuit; at least one integrated circuit mounted on theprinted circuit; and a connector on the printed circuit that receives atleast one of the plurality of separated extending portions and has metalstructures coupled to one or more of the plurality of signal lines. 14.A touch sensor panel comprising: a flexible polymer sheet havingopposing first and second surfaces, wherein the flexible polymer sheetincludes a main portion having a common edge with a main width and oneor more protruding portions having one or more protruding portion widthsless than the main width, the one or more protruding portions protrudingfrom the common edge; capacitive touch sensor electrodes formed on theflexible polymer sheet; and a plurality of signal lines connected to thecapacitive touch sensor electrodes and extending onto the one or moreprotruding portions; wherein the one or more protruding portions includefirst and second sections, the first section including one or more ofthe plurality of signal lines formed only on the first surface and noton the second surface, and the second section including one or more ofthe plurality of signal lines formed only on the second surface and noton the first surface; and wherein the first and second signal lines arenon-overlapping.
 15. The touch sensor panel of claim 14 wherein the mainportion is rectangular and has four edges including the common edge. 16.The touch sensor panel of claim 14, wherein some of the capacitive touchsensor electrodes are formed on the first surface and some of thecapacitive touch sensor electrodes are formed on the second surface,wherein some of the plurality of signal lines are coupled to thecapacitive touch sensor electrodes on the first surface and some of theplurality of signal lines are coupled to the capacitive touch sensorelectrodes on the second surface.